Chemical glassware fittings, especially those provided for micro and sub-micro scale apparatus, is generally equipped with standard male or female tapered endings for cooperation with a mating standard taper surface to effect a joint which both mutually support the apparatus and provide a sealed connection of the parts. The tapered surfaces are ground to standard dimensions with close tolerances.
The part which terminates with a male taper is provided with a shoulder at the juncture of the large end of the taper and the body of the glassware part and the part which ends with a female taper is provided with an annular bead at the end of the part. A clip or clamp is used to hold the engaging taper surfaces together, gripping the shoulder and the bead for this purpose. Generally, a very thin coating of a suitable grease is applied to one of the engaging taper surfaces of a joint or a very thin Teflon gasket is provided to ensure a seal closure at the joint.
These clips and clamps are rather difficult to apply and are not entirely dependable since they may lose their grip on one of the parts, especially if accidentally jarred. There is always the possibility, also, that a joint, thought to be hermetically sealed, may leak, a condition that cannot be tolerated when working in micro and sub-micro scales.
The object of the present invention is to provide improved means for making dependably sealed taper joints in chemical glassware which embody taper connector systems. More specifically, the object is to provide a threaded retainer for taper joints which is capable of applying and maintaining sufficient mutual pressure at the engaging taper surfaces to ensure intimate, sealing contact. A further object is to provide a backup seal to maximize security against leakage at the joint. The backup seal is provided by an O-ring which is held under compressive pressure between a threaded cap and an annular shoulder of the glassware through which the taper joint is retained and the top of the associated part of the joint.